Matt. K wrote:remeber, it is possible to sharpen just a few of the elements in your picture to attract the eye whilst leaving other areas such as clouds or trees a little softer.
thats good advice...
Dave, I think the Topaz filter/preset which also looks like clarity or tonal contrast tweaking has contributed here, look at the horizon on teh right and you can see soft haloing... also on the lighthouse structure, see the different 'coloured' or tonal whites. The Topaz / presets are good, but you need to watch them to ensure you don't head into that 'crunchy' stage since this is when you have heaps of detail and and heaps of dynamic range but the image ends up looking flat, often since there is no light and dark to the image.
in terms of sharpening... look for a white halo line close to edges of objects, a sure sign of too much on the sharpener....
hth